The perennial question of ownership of float returns…
However, I get the impression from some of the posts in this thread that problems some PPers are experiencing is down to not adopting ‘good practice’ in the formulation of their programmes.
I disagree with Bryan’s contention that when you plan works into the future you only need start-start links. In my not so humble opinion I think programmes with loads of dangles are a dangerous thing and might well not demonstrate the reality.
A simple example: a 10-week brickwork activity overlapped by a four week install windows activity. The windows can start after half of the brickwork is complete but when the last of the brickwork is complete only then can the last of the windows be installed. Ideally this would be modelled with, say, a S-S five week lag link and F-F one week lag link. Without the F-F link the windows would be shown completing before the brickwork is complete.
“Ah!”, I hear detractors say, “but that is common-sense and no-one would make such a simple mistake in reality”. The trouble is that is only true on the very simplest of programmes anything more complex and you won’t know what is going on unless you ensure all tasks are constrained in some way at both the start and the finish. Even if it is just linking it to the project start milestone and the project finish milestone.
So, on to float…
My current view on this (which might change tomorrow) is that float is unallocated time within a project. If it is unallocated it belongs to nobody so it is only right that it is available for use by the first person that needs it. Contingency, however, is not unallocated time. It is time that has been specifically set aside to guard against risk of some sort. So, this means that float is not contingency. If you have purposely built in float into your programme for contingency it is my view that you should identify it as such to protect it from use by others. I have suggested, for instance, that buffer tasks could be used to show contingency.
Regards
David
Member for
19 years 10 months
Member for19 years10 months
Submitted by Bryan Russell on Tue, 2006-11-28 04:02
The matter of linking activities in an initial [baseline] programme is to establish a logic flow from start to finish of a project. It may be suitable for that purpose only however the links are structured. What it will not be suitable for is the management of change.
As we all know, the only certainty is that things will change. [Confucius in pre-FIDIC days!] Thus a well structured programme will have front and back links so that the effects of VOs, new drawings, changed quantities, etc can be entered and a new completion date calculated. The matter of the critical path, conventionally shown in red, will follow the line[s] of activities which have no float and will change as each change is entered into the base line programme.
It was a little difficult to follow without the knowledge of planning and use of a planning software but I think I got it.
Obviously, there are terms I am not familiar with but ok.
So what you are saying is if I am to start planning a programme from start, it is best to link each activity FF so incase there is an delay, the link will work it out.
Those programme I saw tends to have a RED line(critical link) they thens to be FS so will a programme FF still show as FS?
Is there any effect on the critical path if planned as FF?
Thanks
Member for
19 years
Member for19 years
Submitted by Tahir Naseem P… on Mon, 2006-11-27 18:24
The other benefits of FF relegation that related activities will not appears illogical in schedule after updating. Such as in example
1-The fabrication of spool duration is 10 days
2-erection of spool also 10 days
3-hydrotesting is 2 days.
We need to finish with in 15 days so if we use the relationship SS with lag
Activity 2 SS with lag 3 days and activity 3 with FS of activity 2.
Now after 5 days only 5 % of fabrication completed and erection will not start due to poor progress of fabrication, after updating the plan and reschedule it the fabrication activity will need still 10 more days to complete and the finish date of erection is same as finish date of fabrication which is totally unacceptable while if we use FF link with same lag of 3 days the erection activity always finish three days after finish date of fabrication whatever the progress.
Member for
19 years 10 months
Member for19 years10 months
Submitted by Bryan Russell on Mon, 2006-11-27 03:35
When you plan works in the future, start-start is adequate; however, if you want to use your programme to demonstrate extensions of time it will not do so.
The simple example of 10 days excavating a trench, 6 days pipelaying started with a 5 day lag, then 3 days backfill with a 4 day lag; gives a total of 12 days work.
If the RE instructs the invert level to be 50% deeper, excavation will take say 60% longer, i.e. 16 days, which will have no effect if plugged into a S-S programme, which will show the pipelaying and backfill being done before the excavation is complete.
Finish-finish will immediately show the correct extension of time.
For the best results, you need links at both start and finish of the activities; have a look at CCS on www.ccssa.com
I have no connection with them, just use their software which is unique.
I Want to know from you! im planing for 75 story building. the master programm which is to be the part of contract has float ( Some are unrealistic like 400 Days or more) coz at this level we not developed the programm in detail only I bar per floor for finishing and 7 days per floor for structure but single bar for gf to 5 , 6 to 10 etc.. Once the engineer approve the programm is it necessary to show the same float ( Coz when i started devloping detailed programm floats relatively less .... what to do... also im affried they may use this float to cover their delay of document release.
Member for
19 years 2 months
Member for19 years2 months
Submitted by ashraf alawady on Sat, 2006-09-09 10:17
The float has to be used fo the benefit of the project.
The preperation of the works programme is the contractor s sole responsibilities.
The engineer/client have the right to review and comment on the submitted programme to comply with the contract technical and contractual requirements.
after approving the programme ,the owner of the float found in the programme could be the conractor or the client (the first party needed to use the float)since ,the available floats in the activities of the approved programme can not be prevented from the use by any parties .
Member for
19 years 2 months
Member for19 years2 months
Submitted by ashraf alawady on Sat, 2006-09-09 10:15
The float has to be used fo the beineft of the project.
The preperation of the works programme is the contractor s sole responsibilities.
The engineer/client have the right to review and comment on the submitted programme to comply with the contract technical and contractual requirements.
after appoving the programme ,the owner of the float found in the programme could be the conractor or the client (the first party needed to use the float)since ,the available floats in the activities of the approved programme can not be prevented from the use by any parties .
Member for
23 years 6 monthsRE: Float Owner?
Dear all
The perennial question of ownership of float returns…
However, I get the impression from some of the posts in this thread that problems some PPers are experiencing is down to not adopting ‘good practice’ in the formulation of their programmes.
I disagree with Bryan’s contention that when you plan works into the future you only need start-start links. In my not so humble opinion I think programmes with loads of dangles are a dangerous thing and might well not demonstrate the reality.
A simple example: a 10-week brickwork activity overlapped by a four week install windows activity. The windows can start after half of the brickwork is complete but when the last of the brickwork is complete only then can the last of the windows be installed. Ideally this would be modelled with, say, a S-S five week lag link and F-F one week lag link. Without the F-F link the windows would be shown completing before the brickwork is complete.
“Ah!”, I hear detractors say, “but that is common-sense and no-one would make such a simple mistake in reality”. The trouble is that is only true on the very simplest of programmes anything more complex and you won’t know what is going on unless you ensure all tasks are constrained in some way at both the start and the finish. Even if it is just linking it to the project start milestone and the project finish milestone.
So, on to float…
My current view on this (which might change tomorrow) is that float is unallocated time within a project. If it is unallocated it belongs to nobody so it is only right that it is available for use by the first person that needs it. Contingency, however, is not unallocated time. It is time that has been specifically set aside to guard against risk of some sort. So, this means that float is not contingency. If you have purposely built in float into your programme for contingency it is my view that you should identify it as such to protect it from use by others. I have suggested, for instance, that buffer tasks could be used to show contingency.
Regards
David
Member for
19 years 10 monthsRE: Float Owner?
Skan,
The matter of linking activities in an initial [baseline] programme is to establish a logic flow from start to finish of a project. It may be suitable for that purpose only however the links are structured. What it will not be suitable for is the management of change.
As we all know, the only certainty is that things will change. [Confucius in pre-FIDIC days!] Thus a well structured programme will have front and back links so that the effects of VOs, new drawings, changed quantities, etc can be entered and a new completion date calculated. The matter of the critical path, conventionally shown in red, will follow the line[s] of activities which have no float and will change as each change is entered into the base line programme.
Member for
19 years 5 monthsRE: Float Owner?
Hi,
Thanks to both of you.
It was a little difficult to follow without the knowledge of planning and use of a planning software but I think I got it.
Obviously, there are terms I am not familiar with but ok.
So what you are saying is if I am to start planning a programme from start, it is best to link each activity FF so incase there is an delay, the link will work it out.
Those programme I saw tends to have a RED line(critical link) they thens to be FS so will a programme FF still show as FS?
Is there any effect on the critical path if planned as FF?
Thanks
Member for
19 yearsRE: Float Owner?
Dear skan
The other benefits of FF relegation that related activities will not appears illogical in schedule after updating. Such as in example
1-The fabrication of spool duration is 10 days
2-erection of spool also 10 days
3-hydrotesting is 2 days.
We need to finish with in 15 days so if we use the relationship SS with lag
Activity 2 SS with lag 3 days and activity 3 with FS of activity 2.
Now after 5 days only 5 % of fabrication completed and erection will not start due to poor progress of fabrication, after updating the plan and reschedule it the fabrication activity will need still 10 more days to complete and the finish date of erection is same as finish date of fabrication which is totally unacceptable while if we use FF link with same lag of 3 days the erection activity always finish three days after finish date of fabrication whatever the progress.
Member for
19 years 10 monthsRE: Float Owner?
Skan,
When you plan works in the future, start-start is adequate; however, if you want to use your programme to demonstrate extensions of time it will not do so.
The simple example of 10 days excavating a trench, 6 days pipelaying started with a 5 day lag, then 3 days backfill with a 4 day lag; gives a total of 12 days work.
If the RE instructs the invert level to be 50% deeper, excavation will take say 60% longer, i.e. 16 days, which will have no effect if plugged into a S-S programme, which will show the pipelaying and backfill being done before the excavation is complete.
Finish-finish will immediately show the correct extension of time.
For the best results, you need links at both start and finish of the activities; have a look at CCS on www.ccssa.com
I have no connection with them, just use their software which is unique.
All the best
Member for
19 years 5 monthsRE: Float Owner?
Hi,
Cant help to interupt but hope someone can explain to be why & when to use the following:( I am not a planner)
I can understand in a programme, the finish to start,
Start to start,
But why finish to finish and strt to finish?
When do one use these and if planning or producing a programme which activities or when one put the two above in the programme?
Thanks
Member for
20 years 10 monthsRE: Float Owner?
Santhosh,
It seems as if your programme needs some more links in it - Finish to Finish by the sound of it.
Member for
19 years 3 monthsRE: Float Owner?
Dear ashraf ,
I Want to know from you! im planing for 75 story building. the master programm which is to be the part of contract has float ( Some are unrealistic like 400 Days or more) coz at this level we not developed the programm in detail only I bar per floor for finishing and 7 days per floor for structure but single bar for gf to 5 , 6 to 10 etc.. Once the engineer approve the programm is it necessary to show the same float ( Coz when i started devloping detailed programm floats relatively less .... what to do... also im affried they may use this float to cover their delay of document release.
Member for
19 years 2 monthsRE: Float Owner?
The float has to be used fo the benefit of the project.
The preperation of the works programme is the contractor s sole responsibilities.
The engineer/client have the right to review and comment on the submitted programme to comply with the contract technical and contractual requirements.
after approving the programme ,the owner of the float found in the programme could be the conractor or the client (the first party needed to use the float)since ,the available floats in the activities of the approved programme can not be prevented from the use by any parties .
Member for
19 years 2 monthsRE: Float Owner?
The float has to be used fo the beineft of the project.
The preperation of the works programme is the contractor s sole responsibilities.
The engineer/client have the right to review and comment on the submitted programme to comply with the contract technical and contractual requirements.
after appoving the programme ,the owner of the float found in the programme could be the conractor or the client (the first party needed to use the float)since ,the available floats in the activities of the approved programme can not be prevented from the use by any parties .